Design, Modeling, Lab, and Field Tests of a Mechanical-Motion-Rectifier-Based Energy Harvester Using a Ball-Screw Mechanism

In this paper, a new-type of mechanical-motion-rectifier-based energy harvesting shock absorber using a ball-screw mechanism and two one-way clutches is proposed to replace conventional oil dampers in vehicle suspensions. The proposed energy-harvesting shock absorber can work as a controllable shock absorber as well as an energy harvester. The challenge to harvest energy from reciprocating suspension vibration is solved by integrating a mechanical motion rectifier in the proposed design, which can convert reciprocating vibration into unidirectional rotation of a generator. As a result, the proposed shock absorber achieves high energy-harvesting efficiency by enabling the generator to rotate at a relatively steady speed during irregular vibrations and improves system reliability by reducing impact forces in transmission gears. In addition, the backlash of the proposed shock absorber is significantly reduced due to the use of the ball-screw mechanism, which further increases transmission durability and efficiency. Lab and field tests are carried out to experimentally characterize the proposed energy-harvesting shock absorber. The field testing results show that, when the modified vehicle is driven on a paved road at 40 mph, the proposed energy-harvesting shock absorber is able to reduce the root-mean-square value of chassis acceleration by 11.12% over the oil shock absorber and simultaneously harvest an average power of 13.3 W for a representative period of 8 s.